<template>
  <div>
    <router-link
      tag='div'
      to='/'
      class="header-abs"
      v-show="showAbs"
    >
      <div class="iconfont header-abs-back">&#xe624;</div>
    </router-link>
    <div
      class="header-fixed"
      v-show="!showAbs"
      :style="opcityStyle"
    >
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe624;</div>
      </router-link>
      景点详情
    </div>
  </div>

</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opcityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = (top - 60) / 80
        opacity = opacity > 1 ? 1 : opacity
        this.opcityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
        this.opcityStyle.opacity = 0
      }
    }
  },
  mounted () {
    // document.documentElement.scrollTop = 0
    window.addEventListener('scroll', this.handleScroll)
  },
  destroy () {
    // document.documentElement.scrollTop = 0
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles.styl';

.header-abs {
  position: absolute;
  left: 0.2rem;
  top: 0.2rem;
  width: 0.8rem;
  height: 0.8rem;
  line-height: 0.8rem;
  border-radius: 0.4rem;
  text-align: center;
  background: rgba(0, 0, 0, 0.7);

  .header-abs-back {
    color: #fff;
    font-size: 0.32rem;
  }
}

.header-fixed {
  z-index: 2;
  position: fixed;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
  height: $headerHeight;
  line-height: $headerHeight;
  text-align: center;
  color: #fff;
  background: $bgColor;
  font-size: 0.32rem;

  .header-fixed-back {
    float: left;
    width: 0.64rem;
    text-align: center;
    font-size: 0.4rem;
    color: #fff;
  }

  &::after {
    content: '';
    float: right;
    width: 0.64rem;
    height: 100%;
  }
}
</style>
